#include <bits/stdc++.h>
#define int long long
using namespace std;
const int nmax = 1e5;
const int Mod = 1e9 + 7;
int n,q;
vector<int> G[nmax + 5];
int add[nmax + 5];
bool sw[nmax + 5];
int put[nmax + 5];
vector<int> l[nmax + 5];
int r[nmax + 5];
int rez, nr_grup;
struct dsu
{
int t[nmax + 5], rang[nmax + 5];
stack<pair<int,int> > st;
dsu()
{
for(int i=1;i<=nmax;i++)
{
t[i] = i;
rang[i] = 1;
}
}
int reprezentant(int x)
{
if(t[x]==x)
{
return x;
}
return reprezentant(t[x]);
}
void uneste(int x, int y)
{
x = reprezentant(x);
y = reprezentant(y);
st.push({x,y});
if(x==y)
{
return;
}
if(rang[x] < rang[y])
{
swap(x,y);
}
rez -= (put[rang[x]] + put[rang[y]]) % Mod;
rez += Mod;
rez %= Mod;
t[y] = x;
rang[x] += rang[y];
rez += put[rang[x]];
rez %= Mod;
--nr_grup;
}
void undo()
{
int x = st.top().first;
int y = st.top().second;
st.pop();
if(x==y)
{
return;
}
if(t[x]==y)
{
swap(x,y);
}
rez -= put[rang[x]];
rez += Mod;
rez %= Mod;
t[y] = y;
rang[x] -= rang[y];
rez += (put[rang[x]] + put[rang[y]]) % Mod;
rez %= Mod;
++nr_grup;
}
}d;
void Add(int nod)
{
sw[nod] = true;
rez += 2;
rez %= Mod;
++nr_grup;
for(auto it : G[nod])
{
if(sw[it])
{
d.uneste(nod,it);
}
}
}
void Remove(int nod)
{
for(auto it : G[nod])
{
if(sw[it])
{
d.undo();
}
}
--nr_grup;
rez -= 2;
rez += Mod;
rez %= Mod;
sw[nod] = false;
}
void solve(int nod, int a, int b)
{
for(auto it : l[nod])
{
Add(it);
}
if(a==b)
{
r[a] = (rez - nr_grup + Mod) % Mod;
for(auto it : l[nod])
{
Remove(it);
}
return;
}
int mij = (a + b) >> 1;
solve(nod*2,a,mij);
solve(nod*2+1,mij+1,b);
for(auto it : l[nod])
{
Remove(it);
}
}
void update(int nod_gr, int ua, int ub, int nod, int a, int b)
{
if(ua<=a && ub>=b)
{
l[nod].push_back(nod_gr);
return;
}
int mij = (a + b) >> 1;
if(ua<=mij)
{
update(nod_gr,ua,ub,nod*2,a,mij);
}
if(ub>mij)
{
update(nod_gr,ua,ub,nod*2+1,mij+1,b);
}
}
signed main()
{
freopen("nr.in","r",stdin);
freopen("nr.out","w",stdout);
cin>>n>>q;
put[0] = 1;
for(int i=1;i<=n;i++)
{
put[i] = 2LL * put[i - 1] % Mod;
}
for(int i=1;i<n;i++)
{
int x,y;
cin>>x>>y;
G[x].push_back(y);
G[y].push_back(x);
}
for(int i=1;i<=n;i++)
{
int val;
cin>>val;
if(val==0)
{
add[i] = 0;
}
else
{
add[i] = -1;
}
}
for(int i=1;i<=q;i++)
{
int nod;
cin>>nod;
if(add[nod]==-1)
{
add[nod] = i;
}
else
{
update(nod,add[nod],i-1,1,0,q);
add[nod] = -1;
}
}
for(int i=1;i<=n;i++)
{
if(add[i]!=-1)
{
update(i,add[i],n,1,0,q);
}
}
solve(1,0,q);
for(int i=0;i<=q;i++)
{
cout<<r[i]<<'\n';
}
return 0;
}
Compilation message
robots.cpp: In function 'int main()':
robots.cpp:173:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
173 | freopen("nr.in","r",stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~
robots.cpp:174:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
174 | freopen("nr.out","w",stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
9048 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
9048 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
9048 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
9048 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
